Backyard Aquaponics
A place to discuss aquaponics

hmmmm, interesting sampling method!

i might put a bit of pumpkin in mine. when ever i put it in the worm farm it is COVERED with worms.

I wanted to see if my pawpaw was throwing new roots - so I pulled the net pot out of my bed today to take a look. I also need to make sure it doesn't establish itself in this bed - cause I need to move it to a satelite pot as soon as I set one up.

Looks like it is doing fine.

Doesn't take long eh!

No it doesn't - not sure what sort of root development there is in the perlite, but there must be some. I'll have to get my arse into gear and organise one of my 180 litre round poly tanks as a grow-bed for the paw paw.

Do you know how long it takes to get fruit from a tree that is that size, I mean how long to grow big enough in normal conditions ie dirt

less than a year I think

wow

The work today and yesterday has paid off. From last night the autosiphon was working without a hitch - reducing the flow did the trick. From when it started sucking some air through the airpipe and crenulations it would take about 1.5 minutes for the siphon to break. Seemed reliable. The reason I speak in the past tense is that I have now done some significant changes to the system for which I first needed to get the autosiphon working.

I have hooked up a 1000 litre round fibreglass tank (purpose built for aquaculture - I got it second hand) and transferred my fish to this. The pond that I previously had my fish in is now the sump. To this pond I used to have another connected with a 5 inch pipe (no fish - but it meant a greater volume of water and therefore less of a drop in level during the flood cycle). The connection between the ponds is now plugged - with just the 1 acting as the sump. The other is dry and will be removed when I get a chance.

How the system now operates:

I have a pond pump in the sump, which pumps water to the fish tank. It has a venturi fitting at the end - which creates a heap of aeration (great little device - I got it from Murray). At the moment the water id just going through 16mm (or is it 19mm??) clear vinyl hose - but when I have the necessary fittings I will replace this with something that is not clear and which is rigid (PVC I guess).

The fish tank has a central drain that takes 80mm pressure pipe. Fitted into this drain (vertically) I have a length of 80mm pressure pipe. The top of the pipe sits about 10cm below the top of the tank. Water flows over the top of this standpipe and travels down the standpipe, through the drain, into some 25mm PVC pipe and into the grow-bed. At present the water is just flowing out the end of the 25mm pipe into a single spot in the grow-bed. When I get a chance I will hook it into a grid of some type.


When the bed fills, my autosiphon kicks in and empties the bed. The venturi attachment - as well as the additional pumping height to the fish tank - has had the effect of reducing the flow of water to one that allows the autosiphon to stop by itself. This has meant that I have been able to dispense with the tap that I was using to reduce the pump flow to get the siphon to work properly. I haven't times the flood/drain cycle, but I will at some point. When the grow-bed is flooded, the sump is about half full - when the grow-bed drains, the sump is full.

The pump is on continuously - so there is always flow to the fish tank (and aeration from the venturi) and there is always a draining action from the fish tank to the grow-bed.

At the moment the water is just flowing over the top of the standpipe in the fish tank - which is not ideal because it doesn't remove the solids that settle in the middle of the tank. During the week I will buy a length of 100mm pipe and fit this over the top of the 80mm standpipe in a way that will result in the water flowing over the standpipe being pulled from the bottom of the tank (like MF's system).

As always it was a challenge catching the fish - but got them in the end. They seem happy enough in their new tank. The water is pretty grubby - because all the solids that were in the pond (now sump) got stirred up and pumped into the fish tank. These will settle, but until I get fit the 100mm pipe the solids will remain in the fish tank.

I also need to put some sort of cover over the tank because my fish would not be keen to get the amount of light they would get otherwise.

I will post a series of pictures over a couple of posts.

more pics

and more

Last ones.

Edit: I have now included a new shot of the standpipe with the outer pipe installed over the top. In the pictures and commentary of my redesigned sytem (see the last few posts) I was yet to install the outer pipe in the fish tank (the one that goes over the 80mm standpipe). I had not done this at that stage because I had no 100mm pipe on hand. A couple of days later I bought some 100mm pipe and installed it. I simply cut crenelations in the bottom of the pipe and put the pipe straight over the top of the 80mm standpipe. The outer pipe (100mm pipe) is about 5-7cm taller than the inner pipe (80mm pipe installed in the drain). The effect is that the water flowing over the inner pipe and out to the grow-bed is drawn from the bottom of the tank and up between the outer and inner pipes. Because the outer pipe is not capped a siphon does not start which would cause the tank to empty. Also, it should be noted that this outer pipe, although higher than the water level - is lower than the top of the tank. This means that if the space between the inner and outer pipes gets blocked - the water will simply rise and exit throught the insde pipe after overflowing over the outside pipe.

Result of all this, and the whirlpool action of my tank, is that any poo ends up exiting the tank within no time of it coming out of a fishes bum. Similarly - any food which sinks and is not eaten gets removed to grow-bed very quickly (I use floating food).

Magnificent VB

Do you think you could flood multiple beds by this method?

Sure can - just need to regulate how much water is going to each bed using taps, and of course have the pump from the sump pumping more into the fish tank.

Right. But you need to have fall from the fish tank to the growbeds, but with the water level being constant, not much fall would be required am I right?
Also, what happens if the pump fails? Can the sump handle the volume of water that could possibly be in the growbed, then the fish tank stays full and the sump stays full until the pump kicks in again? If so, you have nailed it.

You will see that I have put the tank on some besser blocks. I only did this to build in an extra margin (for error I guess), in reality the level of the entry into the bed would not need to be much lower than the top of the standpipe.

If pump fails - the water in the fish tank stays at the height of the top of the standpipe. Depending on how the syphons are set up - water will either stay in the beds or return to the sump. I intend to have a small hole in the syphon setup that will allow water to drain out of the beds if I choose to turn the pump off at night. The sump needs to be big enough to hold the volume of what all the grow-beds take on the flood cycle - plus enough to allow the pump to run and to to cater for water loss through evaporation and transpiration (plus what will be in pipes). My pond is plenty for the 1 grow-bed - but for my big system I will be using Murray's fish tank as the sump (dug into ground) 2,300 litres. The sump will also have smaller fish in it.